Sunday, November 19, 2017

Case of the Week 469

The below was seen on a stool agar culture after incubation at room temperature for several days. The patient is a 62-year-old woman from the Philippines. The images are by my awesome lead tech, Heather Rose, while the video is by Emily Fernholz, Education Specialist extraordinare.

The following were seen in the concentrated wet preparation of the stool specimen :

This is most likely a rhabditiform larval stage of Strongyloides stercoralis. Unlike hookworm rhabditiform larvae, the last picture shows a" short buccal cavity " which is typical of Strongyloides.However, two issues are of concern:1. The large oval-shaped genital primordium is not clearly seen as it should.2. The larval motility shown in the video is faster than normal.

This is most likely a rhabditiform larval stage of Strongyloides stercoralis. Unlike hookworm rhabditiform larvae, the last picture shows a" short buccal cavity " which is typical of Strongyloides.However, two issues are of concern:1. The large oval-shaped genital primordium is not clearly seen as it should.2. The larval motility shown in the video is faster than normal.

Definitely a case of S. stercoralis infection, yet given that the stool culture had been at room temperature for several days, we do have a scenario of different development stages being present as in the first picture where there are at least two sizes of larvae present. the highly motile nematodes in the video may simply be the free living adults nematodes.

I agree with Strongyloides stercoralis. Florida Fan is correct: cultures develop different stages, amongst which adults, evolving finally into filariform larvae. The adults may be seen as very motile nematodes on the culture plate. In the first picture I have the impression that indeed different sizes of larvae are present, as well as three eggs (not very clearly visible) containing rolled-up larvae, so the patient's stools should be very runny. In the second picture I think I am able to see a short buccal cavity, together with a genital primordium (top of the larva), which confirms S. stercoralis.

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The Fine Print:Please note that all opinions expressed here are mine and not my employer. Information provided here is for educational purposes only. It is not intended as and does not substitute for medical advice. I do not accept medical consults from patients.